The pyrotechnic initiator, the first component of the pyrotechnic lighting chain, can be activated by various means such as electrical, mechanical, thermal, optical means. These means provide stimuli, more often than not of low amplitude, to activate the initiator. These stimuli, which can be in the normal or accidental environment of the pyrotechnic device, can inopportunely activate the lighter provoking the nominal operation of the pyrotechnic device.
The regulations concerning the ignition of pyrotechnic lighting devices, notably missiles, are constantly changing toward greater safety, for example by the application of NATO standards.
The main safety criterion is that the pyrotechnic device should not be triggered inopportunely. An uncontrolled triggering can involve serious risks to personnel and significant equipment damage.
To avoid the effects of inopportune triggerings, the lighters of the prior art whose lighting chain contains sensitive pyrotechnic compounds, normally comprise a safety switch, for example toggle, slider, rotor, which separates these sensitive compounds from the rest of the pyrotechnic chain, and which can be opened when the lighter is deliberately operated only by the activation of at least one safety device.
Ignition delays are often introduced into the lighters according to parameters associated with the use of the pyrotechnic device, for example to ensure a sufficient safety distance relative to the personnel and equipment to be protected.
These ignition delays can easily be obtained and managed by an electronic circuit receiving an activation signal and supplying an electrical signal delayed by a time t predetermined according to the use of the pyrotechnic device. Such electronic activation-delay generating devices require an electrical energy source and occupy a volume that is sometimes incompatible with the available bulk constraints for certain applications.